1. Field of the Invention
The present invention relates to an optical scanning device, an optical scanning type display and an image data input/output device. Particularly, it relates to an optical scanning device which can be used as an optical scanning portion of an optical scanning type display, the scanning portion being able to be used for an AV equipment field such as a television, a game and the like, or an OA equipment field such as a personal computer, a word processor and the like, or an optical data processing field such as an optical modulation component and an optical operation component, and furthermore it relates to an optical scanning device which can be also used as an optical scanning portion of an image data input/output device of a laser beam printer and the like.
2. Description of the Related Arts
Generally, if a drive signal is transmitted through an electric wire, a transmission of a signal wave form is delayed due to a wire resistance and a floating capacitance. In order to solve this problem, it is desirable to use an optical scanning type display which uses a light as a drive signal.
A construction of a conventional optical scanning type of an active matrix liquid crystal display will be described referring FIG. 11, which display is shown in Japanese Patent Application Laying Open (KOKAI) No. 5-100248 filed by the applicant of this application.
FIG. 12 is a cross sectional view of the device seen from the line H-H' of FIG. 11.
A plurality of light guides Y.sub.1, Y.sub.2, . . . Y.sub.n are arranged along a Y direction on one substrate constituting of a liquid crystal panel, and a plurality of signal electrodes X.sub.1, X.sub.2, . . . X.sub.m are arranged thereon along a X direction so as to cross a plurality of the light guides. A switching component 2 comprising a photoelectric material is disposed on a crossing portion of the light guide Y.sub.n and the signal electrode X.sub.m. The switching component 2 is controlled by an optical signal transmitted from an light-emitting component array 3 through the light guide Y.sub.n. Then, if the light is emitted to the light switching component 2, the light switching component 2 becomes low in impedance, and the signal electrode X.sub.m and a pixel electrode 4 are connected to each other electrically. If the light is not emitted to the light switching component 2, the light switching component 2 becomes high in impedance, and the signal electrode X.sub.m and the pixel electrode 4 are insulated from each other electrically. In other words, the optical scanning type of the liquid crystal display mentioned above is driven by using the light as a scanning signal and utilize an impedance change of the optical switching component 2.
The display requires a back light such as a fluorescent lamp and the like if it is used as a transmission type display, and requires a projecting lamp such as a metal halide lamp and the like if it is used as a projecting type display, whereby a displaying can be performed by modulating the projecting light 7 within the panel. The display can be used as a reflection type display which does not require a back light by using an electrode having reflectivity as the pixel electrode 4.
As a method of scanning an optical signal, for example, there is a method of scanning the light-emitting component array 3 in turn in which semiconductor lasers (LD) or light-emitting diodes (LED) are arranged in the form of the array, as shown in the Japanese Patent Application Laying Open (KOKAI) No. 5-100246 mentioned above. In this case, as means for guiding to the light guide Y.sub.n the light signal emitted from the light-emitting component array 3, there is a lens combination system which converges the light by means of a micro lens array 5 and the like, and a direct combination system in which the light-emitting face of the light-emitting component is adhered directly to an edge face of the light guide Y.sub.n, as shown in Japanese Patent Application Laying Open (KOKAI) No. 5-134151 filed by the applicant of this application.
For example, as shown in Japanese Patent Application Laying Open (KOKAI) No. 1-224727 (Cashio Computer Co.,Ltd), there is a method of forming monolithically the light guide Y.sub.n and the light-emitting component array on the same substrate. In this case, a light-emitting component of a hidrogenated amorphous silicone carbide system (a-Si.sub.x C.sub.1-x :H) which can be formed on glass substrate even at a relatively low temperature, is formed on an edge portion of each of the light guides.
However, there are the following problems in the optical scanning methods of the constructions mentioned above. First, there is a need to provide the LDs in the same number as the light guides, in a case where the LD is used as the light-emitting component array. A hidrogenated amorphous silicone (a-Si:H), which can be formed in a large area on a glass substrate and which has a high response speed and a superiorly optical sensibility, has been widely used as a material for a light switching component constituting of the optical scanning type display. Since the hidrogenated amorphous silicone (a-Si:H) has the high optical sensibility for a light of a wave length of nearly 600 nm, it is desirable that the light signal used in the optical scanning type display has the light of the wave length of nearly 600 nm. However, the LDs on general markets usually have light-emitting wave lengths in a near infrared area, and a LD of an Al--Ga--In--P system (a light-emitting wave length of 670 nm) is generally on the market in respect of the LD of the light-emitting wave length of nearly 600 nm, but it is still much expensive compared to the LD in the near infrared area. Furthermore, most of the short wave LDs are still under improvements. If attempts are made to form the arrays using the LDs with the light-emitting wave length of nearly 600 nm, the arrays themselves will become extremely expensive, resulting in cost increases for the entire display. Therefore, it is not desirable to use the numerous LDs of this type in the form of the array.
Then, when the LED is used as the light-emitting component array, the LED output is very small compared to the LD because of a difference of a light-emitting principle. Moreover generally, similar to the LD, as it approaches the short wave length, it becomes difficult to make large output. In order to get a large output by means of the LED, it is possible to make a light emitting area larger. However, the light of the LED is originally bad in its directivity. The larger the light-emitting area becomes, the worse the light convergence of the lens becomes. Then, an utility efficiency of the light becomes extremely bad. As a result, an extra light which is not used validly is increased, and there may be possibility to have an undesirable effect on a circumference. For example, a display performance would be deteriorated, if the extra light is made into a stray light and is emitted to the light switching component. Therefore, it is not desirable to use the LED in the light-emitting component array.
When the light guide Y.sub.n and the light-emitting component array are formed monolithically on the same substrate, the light-emitting component which can be formed on the glass substrate is only the LED which uses the amorphous material mentioned above. Now, it is difficult to form the LD on the glass substrate. Even if using a LED which is a researched (a-Si.sub.x C.sub.1-x :H) system, it is not sufficient in a reliability and a light-emitting strength.